when you touch vdd to vss you are shorting the whole keyboard and usb, if you where on a 2010 era macbook you would have fried your motherboard... so it reboots and that al diodes flashes tell me that at least they are all powered, although the fact the the last LED is not consistent to me says that it is either not hardware or that it may be a bad solder join with intermittent contact, but as they all power up they all seems to work.
and if you do not want to have dead usb ports try to not short vdd and vss some motherboard do not have proper protection and may fail after a few shorts.